Airline Flybmi has suspended flights and is filing for administration, blaming uncertainty around Brexit.
The airline, which had operated 17 regional jet aircraft on routes to 25 European cities, said all flights were cancelled from Saturday.
Difficulties have included increases in fuel and carbon costs, as well as challenges "particularly those created by Brexit", a statement on the airline's website said.
A total of 376 employees based in the UK, Germany, Sweden and Belgium are employed by bmi Regional.
The statement said: "It is with a heavy heart that we have made this unavoidable announcement today.
"The airline has faced several difficulties, including recent spikes in fuel and carbon costs, the latter arising from the EU's recent decision to exclude UK airlines from full participation in the Emissions Trading Scheme. These issues have undermined efforts to move the airline into profit.
"Current trading and future prospects have also been seriously affected by the uncertainty created by the Brexit process, which has led to our inability to secure valuable flying contracts in Europe and lack of confidence around bmi's ability to continue flying between destinations in Europe.
"Additionally, our situation mirrors wider difficulties in the regional airline industry which have been well documented.
"Against this background, it has become impossible for the airline's shareholders to continue their extensive programme of funding into the business, despite investment totalling over £40 million in the last six years.
"We sincerely regret that this course of action has become the only option open to us, but the challenges, particularly those created by Brexit, have proven to be insurmountable."
Customers have been advised to contact their payment card issuer to get a refund for flights, while those who have booked through a travel agent or partner airlines are advised to contact their agent or airline for details of their options.
Meanwhile Easyjet passengers flying from from Manchester this weekend have been advised to arrive three hours before their flight because an issue with baggage handlers.